Jamno [ˈjamnɔ] (German: Jamunder See) is a lake in northern Poland (in West Pomeranian Voivodeship), close to the Baltic Sea.

It is divided from the sea by a spit, on which lie the resorts of Mielno and Unieście.

Jamno covers an area of over 22 square kilometres (8.5 sq mi); its maximum length is 10.1 kilometres (6.3 mi) and its maximum breadth is 3.4 kilometres (2.1 mi).

An examination of this lake from 2007 shows it is a brackish coastal lagoon that at that time was heavily polluted by sewage from the nearby city of Koszalin.

This West Pomeranian Voivodeship location article is a stub.